title: A rapid quantitative staphylococcal co-agglutination assay. Utilization for the assay of bovine factor VIII-related antigen.
abstract: A simple and rapid technique to measure bovine factor VIII-related antigen has been developed which utilizes protein A-bearing staphylococci and monospecific rabbit antiserum to bovine factor VIII. Staphylococci coated with a specific antibody agglutinate when they are mixed with the specific antigen. We have used an aggregometer to detect an quantitate the agglutination of the antibody-coated staphylococci. The assay has been optimized with respect to amount of antiserum needed for coating staphylococci, concentration of antibody-coated staphylococci, pH and ionic strength of the assay system, and stirring speed of the aggregometer. The staphylococcal co-agglutination assay as monitored by an aggregometer is at least 10 times more sensitive than the conventional slide agglutination method, and can detect as little as 0.1 microgram/ml of factor VIII antigen. It however, cannot be used to quantitate factor VIII-related antigen in plasma, since plasma contains some components which can non-specifically agglutinate staphylococci.
mesh_terms: D000372:Agglutination Tests; D000818:Animals; D000906:Antibodies; D000937:Antigen-Antibody Reactions; D000941:Antigens; D002417:Cattle; D005169:Factor VIII / Q000276:immunology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera / Q000494:pharmacology; D005779:Immunodiffusion; D009994:Osmolar Concentration; D011817:Rabbits; D013211:Staphylococcus aureus; D013997:Time Factors
chemical_list: D000906:Antibodies; D000941:Antigens; D007106:Immune Sera; D005169:Factor VIII